(1) Field of the Invention
The present invention relates to a system for classifying vehicle occupants, which classifies vehicle occupants seated in a seat of a vehicle in order to deploy an airbag only for an occupant of a certain age or older or having a certain physical condition.
(2) Description of the Related Art
Recently, in many cases, an airbag has been installed in a passenger seat, as well as a driver scat, for the safety of vehicle occupants. Such an airbag is deployed when a collision between vehicles occurs, thus protecting vehicle occupants. In the case of an adult, there is no problem in using an airbag, but in the case of a small child, a deployed airbag may act as a dangerous factor that threatens his life thereof.
Therefore, in some foreign countries, the standards of safety evaluation of an actual vehicle occupant seated in a passenger seat for the deployment of an airbag are established, for example, FMVSS 208, CMVSS 208, etc. FIG. 1 illustrates criteria for airbag deployment adopted by most vehicle manufacturing companies to satisfy an FMVSS 208 standard. Referring to FIG. 1, in the case of adults, an airbag is caused to be deployed, but, in the ease of small children 6 years old or younger, an airbag is prevented from being deployed. This is intended to protect small children 6 years old or younger from accidents, using a separate Child Restraint System (CRS), rather than an airbag.
As described above, in order to separately control the deployment of airbags between adults and small children, a vehicle occupant classification system capable of identifying an occupant seated in the seat of a vehicle must be installed in the seat. Some currently-used vehicle occupant classification systems additionally employ the differences between the shapes of the hips of adults and small children, but all fundamentally use the weight difference between adults and small children.
However, the conventional vehicle occupant classification system, which uses the above-commented weight differences between adults and small children as criteria for classification, is problematic in that adaptability to various situations and conditions is poor. An example of this is shown in FIG. 2. That is, typically, the gap between weights required to discriminate between adults and small children 6 years old or younger is set. However, when an adult is not seated with good posture and/or position, there is a risk of the conventional vehicle occupant classification system to erroneously determine such an adult to be a small child of about 6 years old. In this case, the adult will not be protected by an airbag if a car accident occurs. In contrast, there is also a risk of a small child of about 6 years old erroneously being determined to be an adult and thus deploy the airbag.
Further, the conventional vehicle occupant classification system is problematic in that no means for diagnosing internal errors is provided. Since whether an airbag is to be deployed when an accident occurs can be a factor for the occupant's in the car accident, such risk of error must be removed.
Moreover, the conventional vehicle occupant classification system has some drawbacks in that it restricts the design of seats because a plastic mat having a sensor therein must be installed under the cover of a seat, or a separate structure must be installed in the seat.